To enhance your one-handed backhand, bring the racket back using your entire body. Ideally, in the ready position, place your non-dominant hand on throat* of the racket. When you rotate your body, switch your grip with your right hand. Rotate your body and straighten your arm while turning your shoulders.
To execute the motion, turn your shoulders and bring down your racket in a backswing. Ensure that your arm is fairly straight. Aim to bring your hand near your pocket, moving it up and then down close to the pocket. As the ball approaches, begin rotating slightly and propel your racket forward.
When making contact, ensure that you are positioned in front of your front foot. Keep your body sideways and the racket parallel to the net, making contact slightly in front of your body.
After contact, your racket will continue its swing, while your non-dominant hand remains stationary.
That is a counter movement. Therefore, avoid moving your non-dominant hand forward. By the end of the swing, ensure that you are facing forward with the racket, keeping your head upright and on edge.
*Throat: The part of the racket between the head and shaft, also called the heart. Shaft: The section of the racket between the throat and grip. Grip: The part of the racket that the player holds.